How to Create Only One ggplot2 Legend in R (Example Code)

In this tutorial you’ll learn how to create only a single ggplot2 legend in the R programming language.

Setting up the Example

set.seed(876435)                           # Creating random data
my_df <- data.frame(x1 = rnorm(100),
                    x2 = rnorm(100),
                    my_shapes = letters[1:4],
                    my_colors = letters[1:4])
head(my_df)                                # Head of data
#            x1         x2 my_shapes my_colors
# 1  2.60613589  0.2015005         a         a
# 2  0.04928746  0.4702312         b         b
# 3  0.83441786  0.5546141         c         c
# 4 -0.06498267  1.2490154         d         d
# 5  1.75731612 -1.4194633         a         a
# 6  0.06409565  1.2595519         b         b
install.packages("ggplot2")                # Install ggplot2 package
library("ggplot2")                           # Load ggplot2
ggplot(my_df, aes(x = x1, y = x2,          # Creating ggplot2 graph
                  shape = my_shapes,
                  color = my_colors)) +
  geom_point()

r graph figure 1 create only one ggplot2 legend r

Example: Create Shared Legend Using Same Input for shape & color Arguments

ggplot(my_df, aes(x = x1, y = x2,          # Creating ggplot2 graph again
                  shape = my_shapes,
                  color = my_shapes)) +    # Redefine color
  geom_point()

r graph figure 2 create only one ggplot2 legend r

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